Anthraquinone vat dyestuff



Patented Nov. 6, 1928.

UNITED STATES WALTER Mme, or VOHWINKEL, GERMANY, Assrdnoa ro eRAssELLi DYESTUFF con- POBATION, OF NEW YORK, N. Y.,

A ooRronA'rIoN or DELAWARE.

ANTHRAQUINONE VAT D YESTUFF.

No Drawing. Original application filed January 20, 1926, Serial No. 82,588, and in Germany January 21, 1925. Divided and this application filed May 24, 1927. Serial No. 193,949.

This invention relates to the preparation of vat dyestuffs of the anthraquinone series by submitting certain anthraquinone derivatives to an aluminum chloride fusion in the presence of tertiary bases and to certain new products prepared according to this process.

In several German patents, as for example, 136,015, 240,080, 249,000 and 262,788, the fusion of anthraquinone derivatives with aluminum chloride is described. In these patents, the substances are heated to temperatures of 220 to 270 C. in admixture with a large excess of aluminum chloride .(up to 5 parts by weight).

We have found that such fusion can be carried out not only withsmaller amounts of aluminum chloride, as for example, with only one part by weight, but also that it can be carried out at considerably lower temperatures, if aluminum chloride is used in the presence of tertiary bases such as pyridine, quinoline, dimethylanilin, etc. For example, anhydrous aluminum chloride is mixed with one to four times its weight of dry pyridine, and a very well crystallizing compound of both components, which is soluble in excess pyridine, is obtained with evolution of heat, and then the substance that is to be fused is introduced with stirring. Thenit is quickly heated to the reaction temperature which is about 100 C. lower than in the case of'the acid aluminum chloride melts. The reaction product is thus obtained partly in the form of a leuco-compound from which it can be easily isolated by treatment with the oxygen of air. The process just described presents very important advantages over the processes of the patents mentioned. Besides the diminution of the amount of aluminum chloride, the frothing which is very great in the case of the acid melts and which makes the process diflicult, is lessened, and most important of all, thdpresent process yields very pure products directly in excellent yields due to the lower reaction temperature and the presence of a base whereby the injurious efiects of free .tained by the action of aluminum chloride on hydrochloric acid at high temperatures are avoided. While for example, according to German Patent 240,080, 1.1 dianthraquinonylamine yields a brown vat dyestufi on heating to 220 C(with aluminum chloride which is converted into a crystalline yellow dyestufi' only after treatment with sodium hypochlorite at-80 C. according to the process of German Patent 251,021 and with considerable loss of yield, according to Example 1 of the parent application, a product is obtained at 120 0., which on contact with the oxygen of air yields the same yellow dyestufi' in quantitative yields. Organic solvents of a nonbasic nature cannot be used with the aluminum chloride fusion with the same results. For example, according to German Patent 206,464 a reddish-brown vat dyestuff is ob- 2-aminoanthraquinone with nit'robenzol as a diluent, whereas when pyridine is used in place of nitrobenzene, flavanthrene results atabout 180 C. (Example 6) of parent application. Flavanthrene when prepared by melting 2-am1noanthraquinone with aluminum chloride alone, is obtained only at temperatures of 250 to 280 C. (German Patent 136,015).

The invention is illustrated by the following example: I

E trample.

ton from both cold and warm vats, and corresponds probably to the formula:

chemically most likely a carbazol derivative, corresponding probably to the formula:

00 H \P-CHI 25 t I n a0 @[ooT/\I which crystallizes in orange needles, soluble in concentrated sulfuric acid with a deep red color, and producing brownish-orange dyeings on cotton from both cold and hot vat-s. 40

In testimony whereof, I aifix my signature.

WALTER MIEG. 

